The answer to questions like “how many kilograms does a 6 mm wire rope carry?”, “how many tons does a 16 mm rope lift?” or “how much load does a 26 mm rope take?” depends not only on the rope diameter but also on the rope construction, wire grade (1770/1960 MPa), intended use, and safety factor. The same 12 mm wire rope has a minimum breaking load of approximately 8,300 kg as 6×19 FC, 9,400 kg as 6×36 IWRC, and 9,700 kg as 8×36 IWRC. In this guide, we've compiled the breaking load (MBL) and the working load limit (WLL) commonly applied in general lifting for all standard wire rope diameters from 1 mm to 60 mm, for the constructions most used in the industry. We explain how the table is calculated, which diameter matches which tonnage in industry practice, and the most common misreadings made in the field.
How is wire rope breaking load calculated?
The basic formula for wire rope breaking load is quite simple:
MBL (kN) = K × d²
Where K is a constant depending on the rope's construction and wire tensile strength, d is the nominal rope diameter (in mm). K values are approximately in the following range:
| Construction | Wire Tensile Strength | K Value (approximate) |
|---|---|---|
| 6×19 FC | 1770 MPa | 0,330 |
| 6×19 IWRC | 1770 MPa | 0,356 |
| 6×36 FC | 1770 MPa | 0,330 |
| 6×36 IWRC | 1770 MPa | 0,358 |
| 6×36 IWRC | 1960 MPa | 0,396 |
| 8×36 IWRC | 1770 MPa | 0,366 |
| 8×36 IWRC | 1960 MPa | 0,405 |
| 18×7 (rotation-resistant) | 1770 MPa | 0,326 |
| 35×7 (compact non-rotating) | 1960 MPa | 0,395 |
For example, for 16 mm 6×36 IWRC, 1770 MPa: MBL = 0.358 × 16² = 0.358 × 256 = 91.6 kN ≈ 9.350 kg. Using a 5:1 safety factor for general lifting, the WLL is 1.870 kg . For calculation details and the effect of different wire strength classes, see the wire rope breaking load calculation guide you can review it.
quick-reference diameter-to-capacity table from 1 mm to 60 mm
The table below summarizes typical MBL and WLL values (at a 5:1 safety factor) based on the most commonly used 6×36 IWRC (1770 MPa) construction. For other constructions, use the formula above with the corresponding K value.
| Diameter (mm) | MBL (kN) | MBL (kg) | WLL @ 5:1 (kg) | WLL @ 7:1 (kg) |
|---|---|---|---|---|
| 3 | 3,22 | ~330 | ~65 | ~45 |
| 4 | 5,73 | ~585 | ~115 | ~85 |
| 5 | 8,95 | ~915 | ~180 | ~130 |
| 6 | 12,9 | ~1.310 | ~265 | ~190 |
| 8 | 22,9 | ~2.330 | ~470 | ~335 |
| 10 | 35,8 | ~3.650 | ~730 | ~520 |
| 12 | 51,5 | ~5.250 | ~1.050 | ~750 |
| 14 | 70,2 | ~7.150 | ~1.430 | ~1.020 |
| 16 | 91,6 | ~9.350 | ~1.870 | ~1.335 |
| 18 | 116 | ~11.800 | ~2.360 | ~1.685 |
| 20 | 143 | ~14.600 | ~2.920 | ~2.085 |
| 22 | 173 | ~17.650 | ~3.530 | ~2.520 |
| 24 | 206 | ~21.000 | ~4.200 | ~3.000 |
| 26 | 242 | ~24.700 | ~4.940 | ~3.530 |
| 28 | 281 | ~28.650 | ~5.730 | ~4.095 |
| 32 | 367 | ~37.400 | ~7.480 | ~5.340 |
| 36 | 464 | ~47.300 | ~9.460 | ~6.760 |
| 40 | 573 | ~58.400 | ~11.680 | ~8.340 |
| 44 | 693 | ~70.650 | ~14.130 | ~10.090 |
| 48 | 825 | ~84.100 | ~16.820 | ~12.010 |
| 52 | 968 | ~98.700 | ~19.740 | ~14.100 |
| 56 | 1.123 | ~114.500 | ~22.900 | ~16.350 |
| 60 | 1.289 | ~131.400 | ~26.280 | ~18.770 |
Values are nominal and approximate; the figure on the manufacturer's certificate always takes precedence over the table estimate. For ropes with 1960 MPa wire strength, values run approximately 10-12% higher than this table; for FC (fiber core) ropes, they run approximately 6-8% lower.
Which safety factor is used to calculate WLL?
The table above gives two safety factors, 5:1 and 7:1. The value applied differs by sector:
- 5:1: General lifting slings (EN 13414, ASME B30.9). The most commonly used in the table.
- 4:1 – 5:1: Crane and hoist ropes (FEM 9.661, ISO 4308).
- 7:1 – 10:1: Personnel-lifting applications (BS 7905, suspended scaffolding).
- 12:1 – 16:1: Elevator ropes (EN 81-50, EN 12385-5).
- 3:1 – 4:1: Temporary towing or trailer applications (static, short-term).
To select the WLL value, first determine the application type, then divide the MBL by the relevant safety factor. Applying the wrong safety factor is both a regulatory violation and a safety gap. For how the safety factor is defined in each standard, see the wire rope safety factor guide you can use it.
Quick sector matching
| Application | Typical Rope Diameter | Typical WLL Range |
|---|---|---|
| Household wire rope sling (DIY) | 6 – 8 mm | 250 – 500 kg |
| Forklift extension rope | 10 – 12 mm | 700 – 1,000 kg |
| Workshop overhead crane (1-5 t) | 12 – 16 mm | 1,000 – 2,000 kg |
| Tower crane main hoist rope | 16 – 22 mm | 1,800 – 3,500 kg |
| Mobile crane (LR/LTM) | 22 – 32 mm | 3,500 – 7,500 kg |
| Port / container crane | 26 – 40 mm | 5,000 – 12,000 kg |
| Mine cage rope | 32 – 50 mm | 5,000 – 15,000 kg (10:1) |
| Elevator rope (1,000 kg passenger car) | 8 – 13 mm (4-8 pcs) | ~80 kg/rope (12:1) |
| Tremie / bored pile rope | 18 – 26 mm | 2,000 – 4,500 kg |
How many tons does a 16 mm wire rope lift?
For 6×36 IWRC 1770 MPa, the MBL is approximately 9,350 kg, and the WLL at 5:1 is 1,870 kg. So in a direct lifting application with a 16 mm rope, you can safely lift ~1.8-1.9 tons . In a double-rope (two-leg sling) configuration with a proper angle, this value approaches double (with angle correction).
How many kilograms does a 6 mm wire rope carry?
For 6×36 IWRC 1770 MPa, the MBL is approximately 1,310 kg, with a WLL of ~265 kg at 5:1. A 6 mm rope is used for household, light-lifting, and sling applications; for industrial lifting, a minimum of 12 mm is preferred.
Is the IWRC version of a rope stronger than the FC version at the same diameter?
Yes. Because the core of an IWRC (Independent Wire Rope Core) rope is also made of steel, it has approximately 7-10% higher breaking loadthan an FC (Fiber Core) rope of the same diameter. On the other hand, FC rope is somewhat more flexible, lighter, and shows costlier corrosion behavior under moisture. For a comprehensive comparison between IWRC and FC, see the IWRC vs FC rope guide you can take a look.
Which standard are the table values based on?
The MBL values in the table are calculated based on the K coefficients in the EN 12385-4 and ISO 2408 standards. The value given on the manufacturer's certificate is the actual tensile test result for that production batch and may deviate a few percent from the table. Official project calculations should always use the manufacturer's certificate figure.
In which cases is a 7:1 safety factor used instead of 5:1?
A 7:1 safety factor is used for personnel-lifting applications (suspended scaffolding, gondolas, personnel baskets), operations involving shock loads, and substandard maintenance conditions. For elevator ropes, this ratio is between 12:1 and 16:1.
Diameter-to-capacity tables are a starting point for rope selection; the final decision should always take into account the application type, safety factor, sling angle, and the possibility of dynamic loading. The WLL on the label must never be exceeded under any circumstances, and the values in the table should not be interpreted as an unconditional “guaranteed tonnage.”
Yeni Doğan Çelik Halat, has been active in the wire rope industry since 1994, supplying TS EN-certified rope and TSE-certified slings in a wide diameter range from 1 mm to 60 mm to the iron & steel, port, construction, crane, oil, mining, cement, and elevator sectors. Contact us for a diameter and construction recommendation suited to your application.
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